package com.gym.utils;


import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class Different {
    /**
     * date2比date1多的天数
     * @param date1
     * @param date2
     * @return
     */
    public static int differentDays(Date date1, Date date2)
    {
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);

        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        int day1= cal1.get(Calendar.DAY_OF_YEAR);
        int day2 = cal2.get(Calendar.DAY_OF_YEAR);

        int year1 = cal1.get(Calendar.YEAR);
        int year2 = cal2.get(Calendar.YEAR);
        if(year1 != year2) //同一年
        {
            int timeDistance = 0 ;
            for(int i = year1 ; i < year2 ; i ++)
            {
                if(i%4==0 && i%100!=0 || i%400==0) //闰年
                {
                    timeDistance += 366;
                }
                else //不是闰年
                {
                    timeDistance += 365;
                }
            }

            return timeDistance + (day2-day1) ;
        }
        else //不同年
        {
            return day2-day1;
        }
    }

    public static void main(String[] args) throws ParseException {
       /* String dateStr = "2022-03-21";
        String dateStr2 = "2023-03-21";
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        System.out.println("两个日期的差距：" + differentDays(format.parse(dateStr),format.parse(dateStr2)));
    */
        SimpleDateFormat s = new SimpleDateFormat("yyyy-MM-dd");
        Date date=s.parse("2023-03-21");
        System.out.println("输入的日期："+s.format(date));
        Date dateAfter = getDateAfter(date, 30);

        System.out.println("30天后的日期：" + s.format(dateAfter) );
    }

    public static Date getDateAfter(Date d, int day) {
        //Calendar实例
         Calendar calendar = Calendar.getInstance();
        SimpleDateFormat s = new SimpleDateFormat("yyyy-MM-dd");
        calendar.setTime(d);//设置传来的时间
        calendar.add(Calendar.DATE,day);//在这个时间基础上加上n天
        return calendar.getTime();
    }

}
